USB stands for Universal Serial Bus. USB replaces all the different kinds of serial and parallel port connectors with one standardized plug and port combination. With USB-compliant PCs and peripherals, you just plug them in and turn them on. USB makes the whole process automatic. It's like adding instant new capabilities to your PC.

• Supports up to 127 external PC peripherals.
• Industry standard will take the guesswork out of expanding PC functionality.
• Up to an incredible 12 Mbps data transfer rate.
• Cost effective universal connection helps reduce the cost of owning & using PCs & IntelliStations.

The full speed USB bandwidth (up to 12 Mbps) can support a wide range of multimedia and telephone USB devices. The low-speed bandwidth (up to 1.5 Mbps) can support low-cost, low-end devices such as USB keyboard and mice. Simultaneously, USB ports will support both full-speed and low-speed devices .

Connector:

Two types of plugs and receptacles are specified for USB: A Type and B Type. The shielded cable connector will be 4 positions with gold-plated contacts---2 for single on 2mm centerline, 2 for power on 2.5mm centerline.

A Type Plug used for those devices (keyboard, mouse, joystick etc...) on which the external cable is permanently attached.

B Type Plug used for those devices (printer, scanner, modem etc...) that requires an external connector, so that USB cabling is detachable.

Cable:

There are two kinds of cable: Fully-rated and sub-channel. The Main difference between them is that fully-rated can be used for typical peripherals operating at the rated 12 Mbps signaling, while sub-channel 1.5 Mbps signaling.

• Maximum cable length shall not exceed 3M for sub channel or 5M for the fully channel.
• The Shield must be terminated to the connector plug for completed assemblies.